Decelerator device for ball activated downhole tools

ABSTRACT

A decelerator device ( 210 ), or shock absorber, for slowing the speed of a moving ball ( 106 ) approaching a ball seat ( 104 ) anchored in a tool ( 102 ) in a pipe string ( 200 ) of a subterranean well ( 220 ). The decelerator device ( 210 ) has a ball passage ( 208 ), an entrance port ( 204 ) which directs the moving ball ( 106 ) from an open mouth ( 202 ) of the entrance port ( 204 ) to a drag-inducing throat ( 207 ) of the ball passage ( 208 ), and directs the moving ball ( 106 ) towards a ball seat ( 104 ). The body ( 214 ) of the decelerator device ( 210 ) is made of a deformable, solid-state yielding material that displaces away from a centerline ( 103 ) of the ball passage ( 208 ) as the moving ball ( 106 ) with a diameter ( 105 ) larger than the throat ( 207 ) passes through the decelerator device ( 210 ).

FIELD

The present disclosure relates to a device to be used in decelerating the speed of a moving sealing ball in oil and gas well downhole operations.

BACKGROUND

Current ball activated downhole tools require the ball to land on a retainer seat as fluids are pumped down the inside of the work string or casing.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described by way of example with reference to attached figures, wherein:

FIG. 1 illustrates an example of a tool in a downhole environment, according to the present disclosure;

FIG. 2 illustrates a cross-sectional view of a downhole tool housing a ball seat and a ball;

FIG. 3 illustrates a cross-sectional view of a downhole tool housing a ball seat and a decelerator device;

FIG. 4 illustrates a cross-sectional view of a downhole tool housing a ball seat, a decelerator device, and a ball; and

FIG. 5 illustrates a three-dimensional view of a ball seat and accompanying decelerator device having two openings each.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described.

Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the present disclosure.

In the following description, terms such as “upper,” “upward,” “lower,” “downward,” “above,” “below,” “downhole,” “uphole,” “longitudinal,” “lateral,” and the like, as used herein, shall mean in relation to the bottom or furthest extent of, the surrounding wellbore even though the wellbore or portions of it may be deviated or horizontal. Correspondingly, the transverse, axial, lateral, longitudinal, radial, etc., orientations shall mean orientations relative to the orientation of the wellbore or tool.

The present disclosure addresses a shock absorber, or decelerator device, for downhole plug activated tools. The plug can be any number of plugging devices that allow for an aperture to be plugged for activation. Examples of plugging devices include a ball, a dart, oval shaped members, bars, and the like. The plugs can be formed from a variety of different materials depending on the plugging requirements. The reminder of the disclosure uses the term ball as an illustrative example, but present disclosure contemplates using another plug in place of the ball. Thus, the following description of a ball is not limiting. Fluids can be pumped at high flow rates through the tool, which require the ball to encounter a retainer seat face under a high impact load. The high impact of both the initial encounter or impact and subsequent pressure can result in the ball fracturing, thereby losing its ability to seal and build-up pressure. Because a seal and/or pressure build up are required for the ball to perform the designed task of moving a sleeve inside of a downhole tool, current ball designs utilize materials which can withstand these impact loads. For example, current ball materials include metals and high strength composites. However, in some implementations, the ball material must be designed so that it is more fragile and can be drilled through more readily using a standard oil field bit.

Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or can be learned by practice of the herein disclosed principles. The features and advantages of the disclosure can be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the disclosure will become more fully apparent from the following description and appended claims, or can be learned by the practice of the principles set forth herein.

Disclosed is a decelerator device for slowing the speed of a moving sealing ball approaching a ball seat anchored in a pipe string of a subterranean well. The disclosed decelerator device can be incorporated into a ball-actuated downhole tool adapted for interconnection into the pipe string. For example, a ball-actuated tool can have a tool housing within which a ball seat is located, the ball seat having an entrance to a fluid flow channel through the ball seat such that when a ball engages the ball seat the ball seat the ball form a seal therebetween. The fluid flow channel through the ball seat can be cylindrical shaped with a circular flow channel diameter. In addition to a circular flow channel, the flow channel can be square, rectangular, triangular, oval, hexagonal, layered, baffled, and/or fluted. The ball seat flow channel can further be a single hole, such as a single hole baffle, or can be multi-holed.

The decelerator device can have a ball decelerating body with a ball passage therethrough. The ball passage of the decelerator device is designed to have the same interior diameter as the fluid flow channel of the ball seat. In other configurations, the diameter of the decelerator device's ball passage can be larger or smaller than the ball seat fluid flow channel, depending on specific needs of a configuration. The diameter of the decelerator device ball passage can also vary. For example, in certain embodiments the ball passage can be funnel shaped, including an entrance to the ball passage that is at least partially frustoconical.

The ball passage can have a ball entrance port located at the top end of the body that directs a moving ball from an open mouth of the decelerator device into a drag-inducing throat of the ball passage. The ball entrance port can be frustoconically shaped, funnel shaped, annularly shaped, or can be shaped to match the shape of the ball passage. The throat of the ball passage is the portion of the ball passage which makes impeding contact with the ball as the ball passes through the ball passage. The ball passage can have a shape matching the shape of the ball seat flow channel, or can have a distinct shape (circular, square, rectangular, etc.).

The decelerator device, or at least a portion of the decelerator device, has a body constructed from a deformable, solid-state yielding material that displaces away from a centerline of the ball passage as a ball larger than the throat of the ball passage passes therethrough. The deformable, solid-state yielding material can be plastically deformable under subterranean well conditions, where the body is annulus shaped about the throat of the ball passage. In addition, the deformable, solid-state yielding material can continuously extend across the annulus shaped portion of the body. That is, the entirety of the decelerator device, or at least a plane of the decelerator device, is made of the deformable, solid-state yielding material. In other configurations, the deformable, solid-state yielding material can have voids therein while still forming an annulus shaped portion of the body about the throat of the ball passage. For example, the decelerator device can have air pockets (or other gases/materials) within the deformable, solid-state yielding material. These air pockets can provide increases in deformation, reformation, or stability under pressure. In a similar context, the body of the decelerator device can be made of a single material or multiple materials. Exemplary materials include polymers (such as rubber or plastic) and metals (such as lead or brass). Based on the material selected for a particular embodiment, the resulting decelerator device can be plastically deformable and/or elastically deformable under subterranean well conditions. As an example of a material being both elastically and plastically deformable, a material could be selected which is elastically deformable until a threshold compression is encountered, at which point it is plastically deformed and no longer returns to its previous shape.

FIG. 1 illustrates an example of the environment in which a downhole tool 102 configured to the present disclosure can operate. The downhole tool 102 is illustrated as being connected to a drill string or production string 200 within a subterranean well 220. In other embodiments, the downhole tool 102 can be connected to any number of fluid flow devices such that it operates to control flow in at least one direction.

Referring to FIG. 2, a downhole tool 102 houses a ball seat 104 and a ball 106. The ball 106, upon engaging the ball seat 104, forms a seal which prevents fluids from entering the fluid flow channel 107 of the ball seat 104. As illustrated, the ball seat is annular, forming a ring around the interior of the downhole tool 102, and also having an annular fluid flow channel 107 having an inner diameter 108. In other configurations, the downhole tool 102, ball seat 104, and fluid flow channel 107 can have different shapes and/or proportions. For example, the ball seat 104 can be an annulus and the fluid flow channel 107 can be rectangular.

FIG. 3 illustrates a cross-sectional view of a downhole tool 102 having a ball seat 104 and a decelerator device 210 (which in at least one embodiment can be a shock absorbing material). As illustrated, the decelerator device 210 is located adjacent to the ball seat 104. The decelerator device 210 can be coupled to the ball seat 104, or can be uncoupled. If coupled, the decelerator device 210 can be mechanically or chemically attached to the ball seat 104. Examples of chemical bonding include use of a glue or epoxy. Examples of mechanical bonding can include using hardware (such as a dove-tail, dowel pin, or other mechanism) or designing the ball seat 104 and decelerator device 210 such that the decelerator device 210 screws into the ball seat 104. Such a configuration can utilize a ball seat engagement portion of the decelerator device 210 which is used for fixation to the ball seat 104.

The decelerator device 210 can made from a deformable, solid-state yielding material which displaces away from a centerline 103 of the ball passage 208. Exemplary deformable, solid-state yielding materials include polymers, such as rubbers and plastic, and metals such as brass and lead. In other embodiments, the decelerator device 210 can be made of one or more extended members configured to contact the ball 106 as it passes therethrough, such that a gap is formed between the extended members.

As illustrated the ball decelerating body 214 can have a ball passage 208 formed therethrough. The ball passage 208 can include a ball entrance port 204 located at a top end 216 of the body 214 that directs a moving ball (not shown) from an open mouth 202 of the entrance port 204 into a drag-inducing throat 207 of the ball passage 208.

As illustrated, the diameter 212 of the ball passage 208 in the decelerator device 210 can be the same as the diameter 108 of the fluid flow channel 107 of the ball seat 104. In other configurations, the ball passage diameter 212 can vary depending on the shape of the ball passage 208. For example, if the ball passage 208 is funnel shaped, the diameter 212 of the ball passage 208 can narrow while approaching the ball seat 104. The diameter 212 of the ball passage 208 can also be tapered which will increasingly impede travel of a ball as it approaches. As illustrated, the ball passage 208 is funnel shaped such that ball entrance port 204 is frustoconical shaped and the ball passage 207 is cylindrical shaped and a transition 206 is formed therebetween.

In at least one embodiment, the downhole tool 102 can include an adjacent sleeve in which the seat 104 and decelerator device 210 can be mounted. The following description with respect to the downhole tool 102 equally applies to a sleeve of a downhole tool 102 in which the seat 104 and decelerator device 210 are mounted.

As illustrated, the outside diameter 209 of the decelerator device 210 extends to the interior diameter 101 of the downhole tool 102. In other embodiments, the outside diameter 209 of the decelerator device 210 can be smaller than the interior diameter of the tool 102, leaving a gap between the decelerator device 210 and the “wall” of the tool 102. When a gap exists, a ball 106 passing through the ball passage 208 causes deformation of the decelerator device 210, with the decelerator device 210 expanding/deforming into the gap. The gap will reform after the ball 206 extrudes through the ball passage 208 when the material used for the body 214 of the decelerator device is elastically deformable. The length, wall thickness, and material strength (including hardness) of the decelerator device 210 can be designed to accommodate different impact speeds, ball sizes, and ball specific gravities.

FIG. 4 illustrates a cross-sectional view of a downhole tool 102 housing a ball seat 104, a decelerator device 210, and a ball 306. However, in this illustration the ball 106 has passed through the decelerator device 210 and is engaging the ball seat 104, thereby creating a seal over the fluid flow channel 107. As illustrated, a portion of the ball 106 extends into the entrance 109 of the fluid flow channel 107. Because the decelerator device 210 is made of a deformable, solid yielding material, as the ball 106 passed through the ball passage 208 of the decelerator device 210 the decelerator device 210 can be deformed around the ball 106. The deformation can be elastic, such that the decelerator device 210 returns to a previous shape after the ball 106 passes through the ball passage 208, or plastic, such that the decelerator device 210 does not return to a previous shape and remains permanently deformed.

The deformation of the decelerator device 210, which occurs when the diameter 105 of the ball 106 is larger than the diameter 212 of the throat 207 of the ball passage 208, is away from a centerline 103 of the ball passage 208. For example, if the ball 106 is passing down through an annulus shaped decelerator device 210 enroute to the ball seat 104, the ball passage 208 in the middle of the annulus receives the ball 106 at a ball entrance port 204, deforms away from the centerline 103 of the ball passage 208, and continues down through the throat 207 of the ball passage 208 until either passing through the decelerator device 210 or making contact with the ball seat 104. As the ball 106 continues down through the throat 207 of the ball passage 208, the decelerator device 210 can induce drag upon the ball 106, the ball 106 extruding through the decelerator device 210, reducing the ball's velocity, while the decelerator device 210 deforms by compressing away from the centerline 103 of the ball passage 208. Drag created by the ball 106 contacting the throat 207 of the ball passage 208, however the drag-inducing contact does not need to be constant. For example, the throat of the ball passage 208 can have interior ridges or be ribbed such that the ball 106 decelerates upon successive contacts with the throat. When the ball 106 passes by any point in the decelerator device 210, the original shape can return to the decelerator device 210 when the material of the decelerator device body 214 is subjected to elastic deformation. When the material of the decelerator device body 214 is subjected to plastic deformation, the decelerator device 210 does not return to its original shape.

In at least one embodiment, the ball decelerating body 214 can be configured to have a height 219. The height 219 can be configured to reduce impact forces imparted on the ball 106. In one embodiment, the height 219 can be greater than a predetermined height and the ball decelerating body 214 decelerates the ball 106 prior to contacting the ball seat 104. In another embodiment the height 219 can be less than a predetermined height and the ball decelerating body 214 can reduce the shock on the ball 106. In one example, the predetermined height can be half the diameter 105 of the ball 106. In another embodiment, the predetermined height can be a quarter of the diameter 105 of the ball 106.

The height 219 can be configured based on the material of the decelerating body 214 and/or the structure of the decelerating body 214.

FIG. 5 illustrates a three-dimensional view of a ball seat 402 and accompanying decelerator device 408 having two openings each. The number of openings in the decelerator device 408 and ball seat 402 can vary based on the particular use of the downhole tool in which the ball seat 402 and decelerator device 408 are located. In this case, the ball seat 402 has two ball seat entrance ports 404 which provide openings to two fluid flow channels 406, and which help form seals when balls drop into contact with the ball seat. The decelerator device 408, which in practice can be immediately adjacent to and coupled with the ball seat 402, also has two openings, or entrance ports 410. These decelerator device entrance ports 410 direct moving balls into the drag inducing throats 412 of the ball passages, resulting in balls moving at reduced velocities when they come into contact with the ball seat.

The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of decelerators/ball seats having only a single ball passage and seat or multiple ball passages and seats. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, especially in matters of shape, size and arrangement of the parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms used in the attached claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the appended claims. 

1-20. (canceled)
 21. A decelerator device for slowing the speed of a moving sealing ball approaching a ball seat anchored in a pipe string of a subterranean well, the decelerator device comprising: a ball decelerating body having a ball passage therethrough; the ball passage comprising a ball entrance port located at a top end of the body that directs a moving ball from an open mouth of the entrance port into a drag-inducing throat of the ball passage; and at least a portion of the body comprising a deformable, solid-state yielding material that displaces away from a centerline of the ball passage as a ball larger than the throat of the ball passage passes therethrough.
 22. The decelerator device of claim 21, wherein the throat of the ball passage is cylindrical shaped.
 23. The decelerator device of claim 21, wherein the ball entrance port is frustoconical shaped.
 24. The decelerator device of claim 21, wherein the ball passage is funnel shaped.
 25. The decelerator device of claim 21, wherein the deformable, solid-state yielding material is plastically deformable under subterranean well conditions.
 26. The decelerator device of claim 25, wherein the body is annulus shaped about the throat of the ball passage.
 27. The decelerator device of claim 26, wherein the deformable, solid-state yielding material continuously extends across the annulus shaped portion of the body about the throat of the ball passage.
 28. The decelerator device of claim 26, wherein the deformable, solid-state yielding material contains voids therein, in the annulus shaped portion of the body about the throat of the ball passage.
 29. The decelerator device of claim 25, wherein the body further comprises a ball seat engagement portion configured for fixation to a ball seat anchored in a tool of a pipe string of a subterranean well.
 30. The decelerator device of claim 21, wherein the ball decelerating body has a height that is configured to reduce impact forces imparted on the ball.
 31. The decelerator device of claim 30, wherein the height is less than a predetermined height and the ball decelerating body reduces the shock on the ball.
 32. The decelerator device of claim 30, wherein the height is greater than a predetermined height and the ball decelerating body decelerates the ball prior to contacting the ball seat.
 33. The decelerator device of claim 1, wherein the deformable, solid-state yielding material is elastically deformable under subterranean well conditions.
 34. The decelerator device of claim 33, wherein the body is annulus shaped about the throat of the ball passage.
 35. The decelerator device of claim 34, wherein the deformable, solid-state yielding material continuously extends across the annulus shaped portion of the body about the throat of the ball passage.
 36. The decelerator device of claim 34, wherein the deformable, solid-state yielding material contains voids therein, in the annulus shaped portion of the body about the throat of the ball passage.
 37. The decelerator device of claim 33, wherein the body further comprises a ball seat engagement portion configured for fixation to a ball seat anchored in a tool of a pipe string of a subterranean well.
 38. A ball-actuated downhole tool configured to interconnect into a pipe string of a subterranean well, the ball-actuated downhole tool comprising: a tool housing within which a ball seat is located, the ball seat having a ball engaging, sealing surface forming an entrance to a fluid flow channel through the ball seat; the fluid flow channel through the ball seat being cylindrical shaped and having a flow channel diameter; a decelerator device located adjacent the ball seat for slowing the speed of a moving sealing ball approaching the ball seat, the decelerator device comprising: a ball decelerating body having a ball passage therethrough; the ball passage comprising a ball entrance port located at a top end of the body that directs the moving ball from an open mouth of the entrance port into a drag-inducing throat of the ball passage, the throat being cylindrical shaped and having a diameter substantially equal to the diameter of the cylindrical flow channel through the ball seat; and at least a portion of the body forming an annulus about the throat of the ball passage and comprising a deformable, solid-state yielding material that displaces away from a centerline of the ball passage as a sealing ball having a greater diameter than the throat of the ball passage passes through the annulus.
 39. The ball-actuated downhole tool of claim 38, wherein the ball entrance port is frustoconical shaped.
 40. The ball-actuated downhole tool of claim 38, wherein the ball passage is funnel shaped. 